Functionalized carbosilane polymers and photoresist compositions containing the same

Abstract

Linear or branched functionalized polycarbosilanes having an absorbance less than 3.0 μm −1 at 193 nm and a relatively high refractive index are provided. The functionalized polycarbosilanes contain at least one pendant group that is acid labile or aqueous base soluble. Also disclosed are photoresists formulations containing the functionalized polycarbosilanes that are suitable for use in lithography, e.g., immersion lithography.

1. A photoresist composition comprising:
 a photoacid generator; 
 a linear or branched functionalized polycarbosilane having an acid labile functionality and/or an aqueous base soluble functionality, wherein the functionalized polycarbosilane has a refractive index greater than 1.7 and an absorbance less than 3.0 μm −1  at 193 nanometers; and 
 a casting solvent. 
 
     
     
       2. The photoresist composition of  claim 1 , wherein the functionalized polycarbosilane comprises carbosilane units of formula (I): 
       
         
           
           
               
               
           
         
         wherein R 1 , R 2 , R 3 , and R 4  are independently selected from the group consisting of hydrogen, hydrocarbyl moiety, fluorocarbyl moiety, ethers, esters, lactones, groups containing sulfur, groups containing phosphorous, groups containing boron, groups containing silicon, groups containing germanium, groups containing polar functionalities, groups containing acid-labile functionalities, groups containing aqueous base soluble functionalities, groups containing cross linkable functionalities, and at least one polymer chain including a different polycarbosilane chain; and x, y, and n are independently >1 with the proviso that at least one of R 1 , R 2 , R 3 , and R 4  contain the acid-labile functionality and/or the aqueous base soluble functionality. 
       
     
     
       3. The photoresist composition of  claim 2 , wherein y=2 and x=1. 
     
     
       4. The photoresist composition of  claim 1 , wherein the functionalized polycarbosilane is a homopolymer. 
     
     
       5. The photoresist composition of  claim 1 , wherein the functionalized polycarbosilane is a heteropolymer. 
     
     
       6. The photoresist composition of  claim 1 , wherein the functionalized polycarbosilane is a random, a block, or an alternating polymer. 
     
     
       7. The photoresist composition of  claim 1 , wherein the acid labile functionality comprises an ester moiety, an acetal moiety, a ketal moiety, a carbonate moiety, or a combination thereof. 
     
     
       8. The photoresist composition of  claim 1 , wherein the acid-labile functionality is given by at least one of the following: 
       
         
           
           
               
               
           
         
         wherein L is a linking group selected from the group consisting of linear, branched, and substituted alkylenes having 1 to 7 carbon atoms, cycloalkylene having 3 to 17 carbon atoms, alkylcycloalkylene having 4 to 20 carbon atoms, a cycloalkylalkylene having 4 to 20 carbon atoms, and combinations thereof; n =0 or 1; R 5  is selected from the group consisting of hydrocarbyl substituents with a tertiary carbon attachment point, acetal, and ketal; R 6 , R 7  are independently selected from hydrogen, C 1  to C 6  alkyl, fluorinated C 1  to C 6  alkyl groups; R 8  is selected from the group consisting of hydrocarbyl substituents with a tertiary carbon attachment point, acetal, and ketal; R 9 , R 10  are independently selected from hydrogen, C 1  to C 6  alkyl, fluorinated C 1  to C 6  alkyl groups; R 11  is selected from the groups consisting of hydrocarbyl substituents with a tertiary carbon attachment point; m≧1; p≧1; and q≧1. 
       
     
     
       9. The photoresist composition of  claim 8 , wherein the acid-labile functionality is given by II. 
     
     
       10. The photoresist composition of  claim 8 , wherein the acid-labile functionality is given by III. 
     
     
       11. The photoresist composition of  claim 8 , wherein the acid-labile functionality is given by IV. 
     
     
       12. The photoresist composition of  claim 1 , wherein the photoacid generator is selected from the group consisting of (trifluoromethylsulfonyloxy)-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide (“MDT”), (perfluorobutanesulfonyloxy)-bicyclo [2.2.1]hept-5-ene-2,3-dicarboximide, onium salts, aromatic diazonium salts, sulfonium salts, diaryliodonium salts, sulfonic acid esters of N-hydroxyamides or-imides, and combinations thereof. 
     
     
       13. The photoresist composition of  claim 1 , wherein the functionalized polycarbosilane has a formula selected from the group consisting of: 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         wherein a, b, and c are integers that represent a number of repeat units. 
       
     
     
       14. The photoresist composition of  claim 13 , wherein the functionalized carbosilane has a formula given by V. 
     
     
       15. The photoresist composition of  claim 13 , wherein the functionalized carbosilane has a formula given by VI. 
     
     
       16. The photoresist composition of  claim 13 , wherein the functionalized carbosilane has a formula given by VII. 
     
     
       17. The photoresist composition of  claim 13 , wherein the functionalized carbosilane has a formula given by VIII. 
     
     
       18. The photoresist composition of  claim 13 , wherein the functionalized carbosilane has a formula given by IX. 
     
     
       19. The photoresist composition of  claim 13 , wherein the functionalized carbosilane has a formula given by X. 
     
     
       20. The photoresist composition of  claim 13 , wherein the functionalized carbosilane has a formula given by XI. 
     
     
       21. The photoresist composition of  claim 1 , wherein the carbosilane has an acid labile functionality but not an aqueous base functionality. 
     
     
       22. The photoresist composition of  claim 1 , wherein the carbosilane has an aqueous base functionality but not an acid labile functionality. 
     
     
       23. The photoresist composition of  claim 1 , wherein the carbosilane has an acid labile functionality and an aqueous base functionality.